Advanced Persistent Threats are probably the most remarkable events for Information Security in 2011 since they are redefining the infosec landscape from both technology and market perspective.

I consider the recent shopping in the SIEM arena made by IBM and McAfee a sign of the times and a demonstration of this trend. This is not a coincidence: as a matter of fact the only way to stop an APT before it reaches its goal (the Organization data), is an accurate analysis and correlation of data collected by security devices. An APT attack deploys different stages with different tactics, different techniques and different timeframes, which moreover affect different portion of the infrastructure. As a consequence an holistic view and an holistic information management are needed in order to correlate pieces of information spread in different pieces of the networks and collected by different, somewhat heterogeneous and apparently unrelated, security devices.

Consider for instance the typical cycle of an attack carried on by an APT:

Of course the picture does not take into consideration the user, which is the greatest vulnerability (but unfortunately an user does not generate logs except in a verbal format not so easy to analyze for a SIEM). Moreover the model should be multiplied for the numbers of victims since it is “unlikely” that such a similar attack could be performed on a single user at a time.

At the end, however, it is clear that an APT affects different components of the information security infrastructure at different times with different threat vectors:

Usually stage 1 of an APT attack involves a spear phishing E-mail containing appealing subject and argument, and a malicious payload in form of an attachment or a link. In both cases the Email AV or Antispam are impacted in the ingress stream (and should be supposed to detect the attack, am I naive if I suggest that a DNS lookup could have avoided attacks like this?). The impacted security device produce some logs (even if they are not straightforward to detect if the malicious E-mail has not been detected as a possible threat or also has been detected with a low confidence threshold). In this stage of the attack the time interval between the receipt of the e-mail and its reading can take from few minutes up to several hours.

The following stage involves user interaction. Unfortunately there is no human firewall so far (it is something we are working on) but user education (a very rare gift). As a consequence the victim is lured to follow the malicious link or click on the malicious attachment. In the first scenario the user is directed to a compromised (or crafted) web site where he downloads and installs a malware (or also insert some credentials which are used to steal his identity for instance for a remote access login). In the second scenario the user clicks on the attached file that exploits a 0-day vulnerability to install a Remote Administration Tool. The interval between reading the malicious email and installing the RAT takes likely several seconds. In any case Endpoint Security Tools may help to avoid surfing to malicious site or, if leveraging behavioral analysis, to detect anomalous pattern from an application (a 0-day is always a 0-day and often they are released after making reasonably sure not to be detected by traditional AV). Hopefully In both cases some suspicious logs are generated by the endpoint.

RAT Control is the following stage: after installation the malware uses the HTTP protocol to fetch commands from a remote C&C Server. Of course the malicious traffic is forged so that it may be hidden inside legitimate traffic. In any case the traffic pass through Firewalls and NIDS at the perimeter (matching allowed rules on the traffic). In this case both kind of devices should be supposed to produce related logs;

Once in full control of the Attacker, the compromised machine is used as a hop for the attacker to reach other hosts (now he is inside) or also to sweep the internal network looking for the target data. In this case a NIDS/anomaly detector should be able to detect the attack, monitoring, for instance, the number of attempted authentications or wrong logins: that is the way in which Lockheed Martin prevented an attack perpetrated by mean of compromised RSA seeds, and also, during the infamous breach, RSA detected the attack using a technology of anomaly detection Netwitness, acquired by EMC, its parent company immediately after the event.

At this point should be clear that this lethal blend of threats is pushing the security firms to redefine their product strategies, since they face the double crucial challenge to dramatically improve not only their 0-day detection ability, but also to dramatically improve the capability to manage and correlate the data collected from their security solutions.

As far as 0-day detection ability is concerned, next-gen technologies will include processor assisted endpoint security or also a new class of network devices such as DNS Firewalls (thanks to @nientenomi for reporting the article).

As far data management and correlation are concerned, yes of course a SIEM is beautiful concept… until one needs to face the issue of correlation, which definitively mean that often SIEM projects become useless because of correlation patterns, which are too complex and not straightforward. This is the reason why the leading vendors are rushing to include an integrated SIEM technology in their product portfolio in order to provide an out-of-the-box correlation engine optimized for their products. The price to pay will probably be a segmentation and verticalization of SIEM Market in which lead vendors will have their own solution (not so optimized for competitor technologies) at the expense of generalist SIEM vendors.